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Facebook Configuration

Dependency registration, HTTP clients, and rate-limit handling

Registration

FacebookExecutorDependency.RegisterDefaults(services) registers everything the node needs:

Host apps must also add an explicit registration call: alongside the standard DI registration, host bootstrap must force-load this assembly (e.g. via Plugins_RegisterAllNodes(...) in ServiceCollectionExtensionsForAI.cs) so the facebook node type is discoverable at runtime and appears in the workflow designer.

HTTP Clients

Each resource service gets its own named HttpClient, all sharing the same rate-limit handler:

ServiceTimeoutBacks Resource
FacebookPageService30spage
FacebookPostService30spost
FacebookMessageService30smessage
FacebookReactionService30sreactions
FacebookModerationService30smoderation
FacebookMediaService120smedia (longer timeout for photo/video upload calls)

Rate-Limit Handler

FacebookRateLimitHandler is attached as a DelegatingHandler on every one of the clients above. On any HTTP 429 or 5xx response, it automatically retries — up to 3 times, honoring the Graph API's Retry-After header when present and capping the wait at 60 seconds otherwise. Request bodies are cloned before each retry so POST/upload calls resend correctly.

API Endpoint

All requests target a fixed, versioned Graph API base URL:

https://graph.facebook.com/v25.0

This is a compile-time constant (FacebookHttpHelper.ApiBase) — there is no per-environment or per-network override, unlike a blockchain node's mainnet/testnet split. Every call goes to the live Graph API.

Project Layout

The node ships as three .NET 9 projects:

Project Responsibility
BizFirst.Integration.Facebook.Domain Sealed result records per operation, the webhook payload model, and Graph API response shapes. Zero external dependencies.
BizFirst.Integration.Facebook.Services One service per resource (page/post/message/reactions/moderation/media), the shared HTTP helper, rate-limit handler, input validator/normalizer, cursor paginator, and webhook signature validator.
BizFirst.Ai.ExecutionNodes.Social.Facebook The executor: operation routing, config/credential handling, and per-operation info DTOs.
No appsettings.json section required: Unlike nodes that target a configurable network or environment, this node has no dedicated appsettings block — the Graph API base URL is fixed in code, and the Page access token comes entirely from the credential vault or inline config per call. See Authentication.